Carburetor for internalcombustion engines



Oct. 13, 1953 H. F. BORCHERTS 2,655,356

CARBURETOR FOR INTERNAL-COMBUSTION ENGINES Filed D60. 2, 1949 Patented Oct. 13,

CARBURETOR FOR INTERNAL- COMBUSTION ENGINES Herman F. Borcherts, Allison Park, Pa.

Application December 2, 1949, Serial No. 130,743

Claims.

This invention relates to new and useful improvements in carburetors for internal combustion engines, more particularly to low pressure variable spray fuel injectors, and it is among the objects thereof to provide a carburetor of maximum volumetric efficiency at high engine speeds and which shall maintain proper fuel and air ratio throughout part and full throttle range of engine operation.

The invention further provides in combination with a low pressure variable spray fuel injector a turbo manifold which has great advantage over the conventional Venturi type carbureter and which, by employment of a wide and streamlined manifold, necessitates the use of only a single unit where dual throat carbureters are needed.

The invention will become more apparent from a consideration of the accompanying drawing, constituting a part hereof, in which like reference characters designate like parts, and in which:

Fig. 1 is a vertical cross-sectional view of a low pressure variable spray fuel injector with turbo manifold embodying the principles of this invention;

Fig. 2 a cross sectional view thereof taken along the line 22 of Fig. 1; and

Fig. 3 a bottom plan view of a fuel valve embodied in the carbureter shown in Fig. 1.

With reference to the several figures of the drawing, numeral I designates an air horn through which air for mixing with the engine fuel is drawn as indicated by the arrows. A manually operated throttle valve 2 is disposed in a rectangular passage 3 of the air supply duct, and

an air valve 4, biased by a bimetallic spring 5,

Fig. 2, controls the flow of the air to a cylindrical chamber 6 that surrounds the mixing chamber 1 of the carburetor. The throttle valve 2 is provided with a lever 8 which is connected to the foot pedal of an automobile in the conventional manner, and the bimetallic spring element 5 of the air valve 4 is connected to the air valve shaft 9 as shown in Fig. 2, the spring element 5 being disposed in a cylindrical chamber 1 I having inlet and outlet connections [2 and [3, respectively,

for the passage of heated air as indicated by the arrows in Fig. 2.

The mixing chamber 1 is provided with vertical vanes I4 which are angularly disposed with reference to the cylindrical chamber 1, and air passing through the air duct 3 into the mixing chamher 1 is subjected to a rotating motion in passing between the vanes [4 to mix with a rich fuel mixture delivered by the mixing tube I5. The mixture passes downward in a helical path into the manifold Hi, as shown by the arrows in Fig. 1, and to avoid resistance of the flow of the fuel mixture, a cone I! is provided in the center of the manifold IS. The underside of the cone I1 is heated by what may be termed a stove chamber 18 which is connected to the engine exhaust, the heated exhaust gases passing through the stove as shown by the arrows in Fig. 1. Fuel droplets not gasified in the mixing chamber I during the warm-up period of the engine strike the heated surface of the cone and become gasified. The base of the cone forms a circular Well [9 which catches solid fuel that collects in cold weather starting, the fuel being designated by the numeral 20, Fig. l, and will be gasified by the air moving over it and from the heat of the stove l8. Also, the fuel 23 in the well I9 acts as a primer for starting the engine as a small amount of the liquid fuel collects in the well l9 after the engine is shut off, and a small amount of fuel will also pass through, the fuel valve, hereinafter de scribed, until the final fuel pump pressure reaches zero.

Fuel is supplied from a pump at approximately five pounds pressure through the inlet connection 2 I, Fig. l, and flows into a metering groove 22, Figs. 1 and 3, through port 23. The mixing tube I5 is an inverted funnel-shaped tube, the outer surface of which is provided with a series of scooped openings 24, and the part of the air delivered through the duct 3 to the mixing chamber l enters the fuel mixing tube l5 through the scooped openings 24 to mix with the fuel delivered to the mixing tube. The fuel valve is designated by the numeral 25 and has a cone-shaped base 23 that seats in a complementary shaped portion of a valve base designated by the numeral 21. These conical shaped surfaces of the valve and valve base are ground and polished to a snug fit to seal off the valve while permitting free rotation of the same. Fuel is delivered from the inlet 2! through passage 23 to the metering groove 22 from which it passes through a bleeder passage 28 into a vertical passage 29 of the bleeder tube l5. The valve 25 is held in sealing engagement with the seating surface in the base 21 by a coil spring 30 disposed in a seat 3| of the valve housing, one end of the spring 30 pressing against a plunger 3| that rests on a ball bearing 32 to continually exert seating pressure of the valve 25 on its seat without interfering with the free rotation of the valve, which is automatically effected through a gear 33 and a rack 34, the latter having gear tooth engagement with a gear wheel 35 mounted to rotate with the air valve shaft 9.

The valve 25 is normally biased to the idle position of the engine by means of a torsion spring 36, one end of which is locked in the valve housing at 31 and the other end of which is interlocked with the shank of valve 25 at 38.

The tension of spring 36 is adjustable to regulate pressure and volume flow of air past air valve 4, a d the. eie i of the m terin valve 25 from idle. to. full open flqti'pesiti '"is, also controlled by air 'valv4 through the gear and rack mechanism 35 and 34. The differential in pressure on opposite sides of air valve 4 depends on the degree of opening of the throttle, valve 2;. The bimetallic spring 5, Fig. 2, locat d, housing II and acting as a torsion spring on shaft 9 of air valve 4, is wound upto a maximum when cold, in which position it opposes the metering valve spring tensionof spring 36 and thereby partly opens the air valve and metering valve. When the engine warms up, heat from the "surface of theexhaust manifold is drawn into housing. fl through the inlet l2, passing, the bimetallic spring. 5, and then through outlet- L3 into a passage as that connects. with the vertical passage 29- of: the metering valve 2.5. lhe, warm air isuseful in mixing with the fuel when it passes from the bleeder; passage 28.. into the yer:

. tical passage 29! 'Asishown in Rig. 1, any fuel leaking upward along'the wall of valve 25 enters a roove in from which it flows through a passage 4! into the vertical fuel passage 29.

The operation of the. above. described low pressure variable spray fuel in'iector is r e ly as follows.

When the engine is cranked in starting, air is drawn in through the bell horn I byv the engine pistons, and when the throttle. valve 2 is open, the air valve 4 will move in the direction shown by the arrow. This movement will rot t s ar wheel 35 that in turn operates the rack 34 which interacts with the wheel 33 of the metering valve 25, thereby rotating the latter. As shown in Eig. 3, the metering groove 22 extends throu h an arc of 180; and tapers from zero. to its maximum width at the bleeder passage 28.. It also varies in depth from the shallow to the large portion whereby measured volumes of fuel are del vered from the fuel supply passage 23 to the mixing tube l5. When the metering valve 25. is rotated to the position where the maximum wid h and depth of groove registers with the passage 23 the maximum fuel supply is delivered to the mixing tube l5. Groove 22 is referably V- shaped because of the expedience in cutting the groove as it runs out to zero depth and width at one end of the are.

As p u y e p ained t e a r assi nt the stationary vanes 14 in the mixing chamber. 7 is given a swirling or circular motion and moves downward in the form of a helix as shown by the arrow in Fig. 1. 'The circulating air passing into the scoop inlets 24 of the mixing tube l mixes with the liquid fuel passing down the passage 29 and is'further mixed with the air in'tlie mixing chamber so that is thoroughly mixed when it strilgesthe manifold 16 whicl'i'it is delivered to the valve chambers of the engine.

s e hrottle valvs'2 s m pulated t a grea o s psposi ion, the fue va ve 25 is subjected to ro ati'on' through the rack '34to sup l m re q sfiiel o t mis 'e at s whereb he f e supp i p fflportioned thine air sup ly an a preset el as a 'ai'i i the maintained throughout the full range of throttle manipulation.

As previously stated, when the engine is cold the bimetallic torsion spring 5 overcomes the torsion of the fuel valve 36 to partially open the fuel valve independently of the manipulation of the throttle valve 2, so that on starting a small amount of liquid fuel passes to the mixing tube t5f Kfterfstai't i-i g, thefwalgfil air from the manifold passing through the chamberll" will enter the mixing tube through passage 29 to aid in volatilizing the liquid fuel. This heated air warms up the bimetallic spring 5 which expands te w the tension on the torsion spring 36 of th fuel valve, which then operates to maintairi'the Val-W525 in a normal idling position when the throttle, valve 2 is in closed position.

It: is'evidentfrbm'the above description of the invention that the advantages of a low pressure variable spray fuel injector with the turbo maniold o er he nv nti nal e t ri tree ca reter i e bette tol me s e iie en o el is the. engine at high speeds, which results from the stream in d. ma ld d hat it wi main ain pr per. fuel nd a r ratios hreughout art nd mu th ot e ra seshe e a e wer a lie qr float and 9 ac el awr lim O sh a d c nsequen ly he e ca be no. 'g si n Be ay the venturi and around the idli ftuhealso only a, sin uel i ie i r u i i nec ei Wh dual throat carhuretion is used.

A though one em p m n f the, in enti n has been herein illustrated and ie ibed. itwill be evident o th se k l ed n th i s i m s ea il may be ma e i he' 'e j l if the struction without departing from the, principles herein set forth.

c ai 1,- n a 10W Pr ssure variable, s r y fue injector, a fuel mixing chamber, an air Sli ply pases e mml at ng wi h a amb ane larly disposed vanes in said fuel m xing chamber for subjecting the air supplied'to said chamber to a swirling motion, a valve housing above'said chamber, a mixing tube extending from the valve housing into said chamber, a'valve disposed in said housing and having means for metering. fuel to the mixing tube aid v ns and valve housing having complementary conical shaped se faces and said valve having an 'arcuate "groove of gradually diminishing cross section communi eating with a source of fuel supply. ni'e'ans'for sillijecting the valve to rotary mevement'ier va' the fuel delivered to the mixing'tube, an" air, are in th airsui ply passa i i qe ly' repenve to the air flow'iri said passage; Said air, valve being connected to actuate Saidvalve rotating means, whereby the ratio of "the fuel supply to the mixingcha'mber is'directly proportional to t e a ui p y to said, chamber "2,121. 3; low pressure variable spray fuel ini ct rli a u l m x cham er; n air supply passa e commu ca in w h s 'Q a'mber; a gularly disposed vanes in said fuel mixingcha m beiffor. subjecting the air supplied to said chamb r w s l m t n, a valv'e'hqi sin a ove said chamber, a mixing tube'exten ding from the valve housing into said chamber, a valve'dispos'ed iri'sa'id ho s g and havin means i g meter n fuel tothe'm xi s ube a alv a d alv il in having m l me a y en t l sh ed seating' faces and said'valve having an arcuate groove of gradually diminishing cross section communicating with a source of fuel supply,

, s i c ns' heval e o t?! melment for varying the fuel delivered to the mixing tube, and an air valve in the air supply passage automatically responsive to the air flow in said passage, said air valve being connected to actuate said valve rotating means, whereby the ratio of the fuel supply to the mixing chamber is directly proportional to the air supply to said chamber, said valve rotating means comprising gear teeth on the valve body and a rack interacting therewith, said air valve having a gear wheel subject to rotary movement upon movement of the valve, the teeth of which interact with the teeth of said rack.

3. In a variable spray fuel injector, an annular mixing chamber, an air flow passage for said chamber terminating in a housing surrounding said chamber, said mixing chamber having angularly spaced tangentially disposed vanes for directing the air flow into the mixing chamber by a swirling motion, a fuel valve for said chamber comprising a valve housing having a valve chamber and a fuel delivering opening communicating with the mixing chamber, a conically shaped mixing tube connected to the fuel openings and extending a substantial distance into the mixing chamber, said tube having scooped openings for receiving part of the swirling air passing into said mixing chamber to mix with the fuel delivered to said chamber.

4. In a variable spray fuel injector, an annular mixing chamber, an air flow passage for said chamber terminating in a housing surrounding said chamber, said mixing chamber having angularly spaced tangentially disposed vanes for directing the air flow into the mixing chamber by a swirling motion, a fuel valve for said chamber comprising a valve housing having a valve chamber and a fuel delivering opening communicating with the mixing chamber, a conically shaped mixing tube connected to the fuel openings and extending -a, substantial distance into the mixing chamber, said tube having scooped openings for receiving part of the swirling air passing into said mixing chamber to mix with the fuel delivered to said chamber, a cylindrical valve for the valve chamber having a central passage in register with the fuel supply opening to the mixing chamber, a metering groove in said valve 6 i communicating with said central opening, a source of fuel supply connected to the metering groove, and a source of air supply connected to the top of the valve and communicating with the central opening in said valve.

5. In a variable spray fuel injector, a mixing chamber, an air passage leading to said chamber, a fuel valve for delivering fuel to said chamber comprising a valve housing, a cylindrical valve disposed in said housing, a torsion spring normally biasing said valve in a fixed angular position, a rack and gear for subjecting the valve to rotary movement, said valve having an arcuate shaped metering groove connected with a source of fuel supply for metering the fuel delivered to the mixing chamber, an air flow responsive valve disposed in the air passage, and a throttle valve in said air passage, said air flow responsive valve being mounted on a shaft, a gear wheel on said shaft having teeth interacting with the rack for actuating the fuel valve, and a bimetallic torsion element connected to the last-named shaft and disposed in a separate air flow passage connected to a source of heated air, said last named air flow passage being connected to the fuel valve for delivery of warm air through the fuel valve to the fuel supply passage to the mixing chamber, said bimetallic torsion element overcoming the bias of the fuel valve spring to maintain the fuel valve in partially open position when the bimetallic element is at normal temperature.

HERMAN F. BORCHERTS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 999,686 Westaway Aug. 1, 1911 1,270,432 Monosmith June 25, 1918 1,893,511 Trail Jan. 10, 1933 1,981,876 Moore Nov. 27, 1934 1,990,662 Moore Feb. 12, 1935 2,014,907 Myers Sept. 17, 1935 2,135,539 Sinderson Nov. 8, 1938 2,238,333 McCain Apr. 15, 1941 2,457,570 Leibing .i Dec. 28, 1948 

